Refrigeration



Aug. 23, 1932. LENMNG 1,873,435

REFRIGERATION Filed April 9, 1929 5 Sheets-Sheet l INVE TOR, 2 444/ BY ilk Aug. 23,1932. I LENMNG 1 1,873,435

REFRIGERATION Filed April 9. 19 29 5 Sheets-Sheet 3 *i 0 o "1 9 f ENTO'R' fight, M

J JVZJM 41;: ATTORNEY Patented Aug. 23, 1932 UNITED. STATES PATENT 4 orrlcr.

' ALVAB LENNING... OF NEW YORK, N. 'Y., ASSIGNOIt TO ELECTROLUX SERYEL CORPORA- TION OF NEW' YORK, N. Y., A CORPORATION" DELAWARE REFRIGERATION Application filed April 9,

My invention relates, in its more general form, to improvements in means for causing circulation of' liquid by the application of "heat thereto, or' what is commonly termed thermo-siphon circulation.

While my invention is capable of a general and wide use, the particular application herein chosen for purposes of illustration is to a refrigerating apparatus of the absorption type in which circulation of fluids is obtained by forces generated entirely within the system. My invention is employed with advantage, in such an apparatus, to cause circulation of absorption liquid between and through the generator and absorber.

My invention also consists in the application of the new thermo-siphon circulator to refrigeration apparatus and combinations incident thereto.

Among the objects of my invention are: To facilitate starting of circulation when heat is first applied; to assure. that circulation starts in the desired and proper direction; and to provide even circulation.

These, as well as other objects and advantages, will be apparent from the following description, read in connection with the accompanying drawings, on which Fig. 1 shows a known type of thermo siphon liquid lift or circulator;

Fig. 2 shows another known form of'thermosiphon;

Fig. 3 shows one form of thermo-siphon embodying the present invention Fig. 4.- shows another form of thermosiphon embodying the present invention;

Fig. 5 shows still another form of new thermo-siphon Fig. 6 shows still anotherform of new thermo-siphon;

Fig. 7 shows an elevational view, partially in cross-section, of a refrigerating apparatus to which my invention is applied and Fig. 8 is a side view, partially in crosssection, of the apparatus shown in Fig. 7.

Referring more particularly to Fig. 1, reference character 10 indicates a container from which it is desired to circulate or raise liquid to a higher level. A conduit 11 communicates with the lower part of container 10 and ex- 1929. Serial No. 353325.

tends in. a generally downward direction to connect with a spirally wound conduit 12.

00H 12 is a vaporizer to which heat is applied.

A vertical conduit 13 communicates with the other end of coil 12 and extends to the elevation to which it is desired to raise the liquid.

In the apparatus shown in Fig. 2 a small closed vessel 14 is substituted for coil 12 of Fig.1. In this modification of the known type of thermo-siphon, conduit 13 extends downwardly within vaporizer vessel 14 and the conduit, as well as having an open lower end, is preferably provided with one or more apertures 15 in the side thereof.

The operations of these two thermo-siphons is, in general, as follows Before application of heat to coil 12-or.

vessel 14, the liquid levels in conduit 13 and vessel 10 stand in balanced condition. When heat is applied so that. vapor is formed in coil 12 and vessel 14, the liquid column in conduit 13 expands due to the expansion of the fluid in passing into vapor form. This vertical pressure" efiect'oi appreciable value.

With a straight vert-ical,;uniform tube as in Fig. 1 and Fig. 2, the head isthe same for a given amount of liquid anywhere in the tube. This head has a reactionary eifect exerting a force in the direction of vessel 10. In starting a circulator of this kind, a mass of liquid sometimes moves up a distance in con" duit 13 and then moves back giving an oscillation which moves liquid back through conduit 11 and into vessel 10. In some cases, the

reactionary head may even prevent starting the circulation.

I have found that this difficulty in starting may be efiectually overcome by the arrangement shown in Figs. 3, 4 and 5 which, essentially, comprises placing the conduit 13 in an inclined position and with the inclinaton of the upper part of conduit 13 from the Ver- 1 tical greater than that of the lower portion of the conduit In Fig. 3 conduit 13 is in the form of an arc; in Fig. 4 it is wound. in the form of a spiral thenpper turns of which have a greater inclination from the vertical] than do the lower turns; and in Fig. 5 the con duit comprises'a straight, inclined lower portion 16 and a spiral upper portion 17 In this last modification (Fig. 5) the ortion of'the I conduit comprising spiral 17 as a greater inclinationfrom the vertical than does the part comprising the straight portion 16.

- Also, in Fig. 5 the coil.12;is placed in a hori- .out difliculty. The reason for this reduction I in resistance isthat a mass of liquid having a given volume exerts a certain head when in the lower part'of conduit 13, but, due to the increased inclination of the upper part of the conduit from the vertical,'the same amount through conduit 11 to coil 12 or vessel 14.

of liquid exerts a less and less head the further up the conduit it goes. This reduces the.

reactionary head and consequently the tendency for recirculation. This is clearly shown in connection with Fig. 3 where a mass-of liquid having the same length, as measured along the conduit, and hence the same volume,

is shown in different ositions in the conduit.

The vertical distance etween the bottom and top of the mass is what determines the head exerted thereby and it is clear that the height h of the mass in the lower position is greater than the height h of the same mass in the upper position. Hence, when starting an apparatus constructed in accordance with my invention, the first vapor formed in coil 12 or vessel 14 will have a tendency to force liquid therefrom both through conduits 13 and 11.

However, as soon as liquid has been forced a'slight distance in each of these conduits, the

- resistance oifered by the mass in conduit 13 will lie-reduced, as above explained, and it will be forced upwardly through conduit 13 and liquid will 'flow from container 10,

Thus, circulation is assured of starting, and in the desired direction.

. In Fig. 61the same result is obtained by' making the'bo're of conduit 13 larger at the 1 top than at the bottom rather than a uniform bore or cross-section as in the previously described -'embodiments'. Thus, in Fig. 6, a

" given-- volume will have a head proportionate to it while in the lower part, but only ahead proportionate to h when itis in the upper pzrt. While the upper part hasan enlarged re. itnevertheless is still a capillary tube and vapor will not bubble through the liquid contained therein. Obviously, the change of bore may be more abrupt than shown.

In Figures 7 and 8 is shown my invention,

essentially the modification shown in Fig. 5, applied to an absorption refrigerating a'ppa ratus. Reference character indicates a generator centrally'throu'gh which extends a flue 21. A suitable source of heat, such as a gas burner 22, is-arranged to heat flue 21. A conduit 23, having a comparatively large bore, communicates with the upper part of, generator 20 near one end thereof and extends upwardly to within a chamber 24. The upper end of conduit 23 within chamber 24 is open and there are also .one or more holes 25 formed in the side of the conduit near the bottom of the chamber. A conduit 26 connects the upper part of chamber 24 with a rectifier 27. Rectifier 27 is similar to the rectifier shown in Patent N 0. 1,651,410 grant ed on December-6, 1927' to Nils Persson to which reference may be had for a detailed description of its construction and operation. A condenser conduit 28 communicates with the upper part of one leg of rectifier 27, ex" tends in the form of a coil in heat exchange relation with a cooling water conduit 29 and finally communicates with the more central art of the other leg of the rectifier. A conduit 30 communicates with the lower part of rectifier 27, extends within a conduit 31, a gas heat exchanger 32 and "a conduit 33 to within the upper part of an evaporator 34. The interior construction of the heat exchanger 32 and evaporator 34 is substantially the same as that shown in the above referred to Patent No. 1,651,410.'

A conduit 35 connects the bottom of evaporator 34 with oneend of the more central s ace within the heat exchan er and a conuit 36 connects the other end of this space with the lower part of an absorber 10. Ah-

sorber 10 is provided with a series of disks 38 having apertures 39 surrounded by raised rims 40. Conduit 31 connects the top of the absorber with an'end space within heat-ere changer 32 while conduit 33'connects the other end space with the upper part of evaporator34'. A series of tubes extend between and connect the'aforementioned end spaces. A cooling water conduit 41 is in heat exchange relation with absorber 10 and com municates with cooling water conduit 29.

A gas vent 37 is provided which establishes a more or less restricted communication between the upper part of rectifier 27 and the central space in heat exchanger 32.

A conduit 11 communicates with the lower part of absorber 10 and extends within, and comprises the inner pipe 42 of, a concentricpipe liquid heat exchanger .43. Beyond heat exchanger 43 conduit 42 is formed' in a vaporizer coil 12 around one end of flue 21 and thenceextends upwardly, having a portion her 24. The inclination to the vertical of the spiral portion is greater than that of the straight portion 16.

The similarity between the part of the apparatus described in the last aragraph and that shown in, and described in connection with, Fig. 5 will at once be apparent and corresponding structure is designated by like reference characters.

A conduit 44 communicates with generator 20 and leads to the outer; conduit 45 of liquid heat exchanger 43. Aliconduit 46 connects the other end of 45 with the upper part of absorber 10. Conduit 46 is preferably brought in heat exchange relation with cooling water conduit 41, as by welding it to successive turns thereof. I

The operation of this apparatus is substantially as follows:

Assume the apparatus is being started for Y the first time orafter a shut down. An absorptionliquid, such as water, in which is dissolved a refrigerant, for instance ammonia, is contained within generator 20, conduits 23, 11, 16-, 44 and 45 and in coil 12 and in the lower part of absorber 10, spiral 17 and conduit 46. The level of this liquid mag be as shown in absorber 10 in Fig. 7

hen heat is applied to coil 12 ammonia vapor is driven from the solution contained therein. This vapor tends to force the re mainin liquid out of either end of coil 12 but, as as previously been explained, due to the relative inclinations of conduit 16 and spiral 17, flow almost immediately commences upwardly through conduit 16 and spiral 17 into chamber 24. The ammonia vapor passes from chamber 24 through conduit 26 while the liquid passes through apertures 25 into conduit 23 and through this conduit to generator 20. Within the generator the solution is further heated and more ammonia is. driven out of solution and asses upwardly through conduit 23 to cham r 24. Conduit 23 is of large enough bore so that this vapor may bubble upwardly therethrough without interferring with the liquid which is passing downwardly 'therethrough.

The solution now weak in ammonia leaves generator 20 through conduit 44 and flows through conduits 45 and 46 to the upper part of absorber 10. This flow results from the v 1 fact that the point of discharge of spiral 17 j into chamber 24 is above the point of dis- I on charge of conduit 46 intov absorber 10. vIn the absorber the solution absorbs more ammonia,'as will bepresently explained, andthroughconduit 26 to rectifier 27 where en- I trained water vapor is separated out and runs back to chamber 24; The ammonia vapor passes from the rectifier into condenser conduit 28 where it is liquefied due to a reduction in temperature caused-by the abstraction of heat by the cooling water in conduit 29. The liquefied ammonia flows back to rectifier 27, where it aids in the rectification process, as is explained in Patent No. 1,651,410.

From the rectifier the liquefied ammonia passes through conduit 30 to within the upper part of evaporator 34 where it comes in intimate contact with a gas inert with respect admitted through conduit 33. The ammonia evaporates in the presence of the hydrogen and the accompanying absorption of heat produces refrigeration.

The gaseous mixture of ammonia and hydrogen, havin a greater specific gravity than the relatively pure hydrogen, passes downwardly through the evaporator,

to ammonia, for instance hydrogen, which is thr a'ugh conduit 35 to heat exchanger 32 and from he beat exchan or through conduit 36 to the lower part 0 absorber 10. In the absorber the gaseous mixture comes in contact with the weak absorption liquid, which enters through conduit 46. The ammonia gas is absorbed by the liquid but the hydro gen is not and passes from the upper part of the absorber through conduit 31, heat exchanger 32 and conduit 33 back to evaporator 34. Thus, the refrigerating cycle is com pleted.

'The extension of conduit 23 withimchamber 24 provides baflie means interposed in the path of flow of fiuidissuin g from the top of conduit 13 for separating gas from liquid and preventiri g liquid from passing onto the rectifier.

While I have described my. invention particularly as applied to a refrigerating appas ratus, it is to be understood that it is sus-' ceptible to a general application and I amlimited only by the appended claims viewed in the light of the prior art. What I claim is: 1. That improvement in thermo-siphon circulation which consists in raising a quantity of liquid by vapor below the liquidand is raise i 2. In a thermo-siphon dev ce for raising fliquid, a container, at vaporizer,-a conduit 11s reducing the vertical height of the liquid as it last-mentioned conduit being so constructed and arranged thata given volume of liquid therein exerts a greater head in the lower portion thereof than does an equalvolume in the upper portion thereof. p

3. In a thermo-siphone device for raising liquid, a container, a vaporizer, a conduit connecting the container with the vaporizer isfo 'and'a conduit leading upwardly from said vaporizer to a point above the container, the upper part of the last mentioned conduit having a greater inclination from the vertical than the lower part.

4. In a thermo-siphon device for raising liquid, a container, a vaporizer, a conduit extending in a generally downward direction I er head in the lower portion thereof than does an equal volume in the upper'portion thereof.

5. In a thermo-siphon device for raising liquid, a container, a vaporizer, a conduit extendingin a generally downward direction from the container to the. vaporizer and a continuously inclined conduit of uniform cross-section leading upwardly from said vaporizer to a point above the container, the

upper part of the last-mentioned conduit having a reater inclination from the vertical than t e lower part.

- 6. Absorption refrigerating apparatus comprising an absorber, a vaporizer, a conduit connecting the absorber with the vaporizer, a conduit leading upwardly from said vaporizer to a higher level than the absorber chamber, the last-mentioned conduit being so constructed and arranged that a given volume of liquid therein exerts a greater head in the lower portion thereof than does an equal volume in the upper portion thereof and a generatorconnected to receive liquid from said last-mentioned conduit.

7 Absorption refrigerating apparatus comprising an absorber, a vaporizer, a con-- duit connecting the absorber with said vaporizer, a conduit leading upwardly from said vaporizer to a higher level than the absorber, the upper part of the last-mentioned conduit having a greater inclination from the vertical than the lower part and a generator connected to receive liquid from said last-mentioned conduit. 4

8. Absorption refrigerating apparatus comprising an absorber, a vaporizer, a conduit connecting the absorber with said vaporizer, a conduit comprising a lower straight portion and an upper spiral portion leading upwardly from said vaporizer to a level higher than the absorber, the spiral portidn having a greater inclination from the vertical than the straight portion and a generator connected to receive liquid from said lastmentioned conduit. Y

9. Absorption refrigerating comprising an absorber, a va ori'zer, a conduit connecting the absorber'with said vaporizer, a conduit comprising a lower straight portion and an upper spiral portion leading upwardly from said. vaporizer to a level apparatus lower straight portion and an upper spiral portion extending upwardly from said va orizer to a point above the container, the astmentioned conduit being so arranged that a given volume of liquid therein exerts a greater head in the lower portion thereof than does an equal volume in the upper portion thereof.

11. In a thermo-siphon device for raising liquid, a container, a vaporizer, a conduit connecting the container with the vaporizer and a conduit comprising a lower straight portion and an upper spiral portion extending upwardly from said vaporizer to a point above the container, the upper part of the last-mentioned. conduit having a greater inelination from the vertical than the lower art. P 12. In a thermo-siphon devicefor raising liquid, a container, a vaporizer, a conduit. connecting the container with the vaporizer and a conduit leading upwardly from said vaporizer to a point above the container, the upper part of the last mentioned conduit having a greater here than the lower part.

13. In a thermo-siphon device for raising liquid, a container, a vaporizer, a conduit ext-ending in a generally downward direction from the container to the vaporizer and a conduit leading upwardly from said vaporizer to a point above the container, the upper part of the last mentioned conduit having a greater bore than the lower part.

- l4. Absorption refrigerating apparatus comprising an absorber, a vaporizer, a conduit connecting the absorber with said vaporizer, a conduit leading upwardly from said vaporizer to a higher level than the absorber, the upper part of the last mentioned conduit having a greater bore than the lower part and a generator connected to receive liquid from said last mentioned conduit.

In testimony whereof I have aflixed my signature. ALVAR LENNING 

